Interface vibrational modes and interface structure of CdSe/ZnTe superlattices

Interfacial vibrational modes (LFM's) of CdSe/ZnTe superlattice are shown for perfect and atomically rearranged interfaces with four probable exchange configurations. In addition to the IFM at 222, cm(-1) originating from single interface Zn-Se "wrong" bonds (WB's), another IFM at 235 cm(-1) occurs due to atomic rearrangement at the interfaces, which is attributed to double Zn-Se WB's. Raman scattering on both atomic-layer-epitaxy and molecular-beam-epitaxy grown samples is reported. Using the experimental data for the 218 cm(-1) line of LIF as a base for improving calculations, the corresponding LIF2 line is predicted at 228 cm(-1). Experiments failed to detect this line owing to insufficient double WB's with long-range order. This characteristic IFM is observed in an annealed sample, with abnormally strong intensity at 227 cm(-1).